Four carbon compounds such as 1,4-butanediol (also known as butane-1,4-diol or tetramethylene glycol), putrescine, 4-hydroxybutyrate, and gamma 4-aminobutyrate (GABA) are used, for example, for producing plastics and polymers. 1,4-butanediol is used, for example, as a solvent and for producing plastics, Spandex fibers, and polymers such as polyurethane. 1,4-butanediol can be produced from malic anhydride by the Davy process, from acetylene using Reppe chemistry, or from propylene oxide in a multi-step process. Putrescine is used to produce Nylon-4,6 by reacting with adipic acid. Putrescine typically is produced by hydrogenating succinonitrile. However, the methods to produce such compounds typically are energy intensive and/or produce large amounts of by-products.